Latex agglutination assays for detection of non-O157 Shiga toxin-producing Escherichia coli serogroups O26, o45, O103, O111, O121, and O145

Marjorie B. Medina, Weilin L. Shelver, Pina M. Fratamico, Laurie Fortis, Glenn Tillman, Neelam Narang, William C. Cray, Emilio Esteban, Chitrita Debroy

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Latex agglutination assays utilizing polyclonal antibodies were developed for the top six non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups. Rabbit antisera were affinity purified through protein A/G columns, and the isolated immunoglobulins (IgGs) were covalently immobilized onto polystyrene latex particles. The resulting latex-IgG complex had a protein (IgG) load of 0.20 to 0.28 mg/ml in a 1% latex suspension. Optimum conditions for the agglutination assay consisted of utilizing 20 ml of latex-IgG reagent containing 2.0 to 2.8 mg IgG in a 0.5% latex suspension. Agglutination or flocculation was observed almost instantly after mixing the colonies with the latex-IgG, indicating STEC strains. More than 100 target and nontarget strains were tested in more than 3,000 test replicates. All target organisms produced positive results, but three antisera (anti-O26, anti-O103, and anti-O145) cross-reacted with some other STECs. The anti-O103 and anti-O145 latex reagents crossreacted with O26 strains, and the anti-O26 cross-reacted with O103 strains. The latex-IgG reagents are stable for at least 1 year and are easy to prepare. These agglutination assays can be used for identification of presumptive non-O157 STEC colonies from agar media. The techniques used to prepare the latex reagents also can be utilized for testing other STEC serogroups, other E. coli serotypes, or other pathogens to ensure safe foods to consumers.

Original languageEnglish (US)
Pages (from-to)819-826
Number of pages8
JournalJournal of Food Protection
Volume75
Issue number5
DOIs
StatePublished - May 1 2012

All Science Journal Classification (ASJC) codes

  • Food Science
  • Microbiology

Fingerprint Dive into the research topics of 'Latex agglutination assays for detection of non-O157 Shiga toxin-producing Escherichia coli serogroups O26, o45, O103, O111, O121, and O145'. Together they form a unique fingerprint.

Cite this